Although tickets have been on sale by phone and online since June, Mamma Mia! will finally open its box office Aug. 20. The ABBA tuner is already selling very well — a cursory search for tickets on Telecharge.com revealed there were no center orchestra seats available until the middle of February. Of course, Mamma Mia! selling well comes as no surprise; the national tour broke box office records in San Francisco, Los Angeles and Chicago and the London and Toronto productions are still selling out.

Although tickets have been on sale by phone and online since June, Mamma Mia! will finally open its box office Aug. 20. The ABBA tuner is already selling very well — a cursory search for tickets on Telecharge.com revealed there were no center orchestra seats available until the middle of February. Of course, Mamma Mia! selling well comes as no surprise; the national tour broke box office records in San Francisco, Los Angeles and Chicago and the London and Toronto productions are still selling out.

Recently, the Broadway company acquired a full cast. All summer bits and pieces of casting were leaking through. First, Louise Pitre, Dora winner for the Toronto production, announced she would continue to New York as the lead role Donna. Then Karen Mason joined up as her gal pal Tonya. Two Canadians quickly followed, with Toronto replacement cast member David Keeley as Sam and Pitre's Toronto co-star and newcomer Tina Maddigan continuing to Broadway as her daughter Sophie. Finally, Ragtime's Judy Kaye slipped in as another of Donna's friends, Rosie.

Mostly unknowns have stepped into the remaining roles. Joe Machota, who has toured as Ren in Footloose and Joseph in Joseph and the Amazing Technicolor Dreamcoat, is Sophie's fiance, Sky. Dean Nolen (Tabletop) is Harry with Ken Marks (When They Speak of Rita) as Bill.

Mamma Mia! collects a couple dozen hit songs by the Swedish supergroup ABBA and shapes them around the story of a single mother and her young daughter's marriage on a Greek isle. While the daughter plans her future with the love of her life, she and her mother are haunted by three different men who may or may not be her daughter's father. Among the songs used in Mamma Mia! are such familiar 70s staples as "Dancing Queen," "Knowing Me, Knowing You," "S.O.S.," "Take a Chance on Me" and "The Winner Takes It All."

Andersson and Ulvaeus, the songwriting half of ABBA, previously wrote the musical Chess, which enjoyed an extended run at the Prince Edward in the 1980s in a production directed by Trevor Nunn, currently artistic director of the National Theatre.

Mamma Mia! is directed by Phyllida Lloyd and choreographed by Anthony Van Laast. It is designed by Mark Thompson, with lighting design by Howard Harrison, sound design by Andrew Bruce and musical supervision by Martin Koch.

For tickets , call Telecharge at (212) 239-6262. Mamma Mia!, which begins previews Oct. 5 and opens Oct. 18 at the Winter Garden Theatre, is on the web at http://www.mamma mia.com.